APA committee OKs herbicide use in lake

Final vote today; second time Renovate would be used in Park

March 15, 2013

RAY BROOK - A key state Adirondack Park Agency committee has approved a controversial plan to use a herbicide to kill invasive plants in a Warren County lake.

The APA's Regulatory Programs Committee signed off Thursday on the town of Chester's proposal to disperse 1,500 gallons of Renovate OTF in the southeastern corner of Loon Lake. The project will come before the full agency board today and is expected to gain final approval.

The herbicide would be used to kill Eurasian watermilfoil, a stubborn invasive water weed that crowds out native plants and has become a nuisance to boaters and swimmers in waterways across the Park. It would be only the second time Renovate, which goes by the chemical name triclopyr, has been used in the Park. It was applied to Lake Luzerne in 2011, also to control milfoil.

In a presentation to commissioners, APA Environmental Program Specialist Leigh Walrath said the town and the Loon Lake Park District Association have used several other methods to remove milfoil from Loon Lake since it was first spotted in 2000, including harvesting the plants by hand and smothering them with mats called benthic barriers.

In 2010, milfoil was detected at 37 sites on the 586-acre lake. Removal efforts that year cleared 28 of those sites. The following year, however, milfoil was found in 41 locations around the lake. Twenty-nine of those sites were cleared, but by 2012, the invasive was detected at 43 sites.

"This is the kind of Whack-a-Mole game that lake associations tend to play with milfoil," Walrath said.

Article Links

The cost of milfoil removal efforts in Loon Lake have grown from $7,000 in 2005 to $40,000 in 2010 and $55,000 last year. This year, the town will spend an estimated $85,000, $20,000 to $30,000 of which will pay for the Renovate treatment, with the rest being used on continued hand harvesting and benthic barriers.

While milfoil has been found throughout the lake, the herbicide would only be applied to a 15-acre area near the lake's boat launch and outlet. A 600-foot curtain will be stretched across the lake to keep the rest of its water from diluting the concentration of the chemical in the treatment area. A series of monitoring sites will be established both inside and outside the treatment area, including in a downstream wetland.

"We're hoping this treatment will get the area to a low density so the volunteers and lake managers can manage it in a manner that doesn't have the opportunity for the milfoil to be chopped up and transported both in this lake and other lakes," Walrath said. "We expect to reduce the long-term management costs for the control. The town can't sustain the $55,000-a-year management strategy, and the goal, in part, is to help reduce that to $30,000 a year, which is what they believe they can manage long term."

The herbicide is scheduled to be dispersed from a boat on May 13, before many of the lake's native acquatic plants emerge. Adults and children wouldn't be able to swim in the treated area until three hours after, and the use of water in the lake for drinking or food preparation would be prohibited until the chemical's concentration falls below a certain level.

Earlier this week, the Adirondack Council called on the agency to hold a formal public hearing before approving the use of the herbicide, citing what happened during a prior use of Renovate in the Park.

"The APA should not grant another permit to use chemical herbicides in any Adirondack lake until it figures out what went wrong in Lake Luzerne in 2011," Diane Fish, the council's acting executive director, said in a press release. "This chemical killed alarming numbers of snails and suppressed dissolved oxygen to dangerous levels, putting other organisms at risk."

APA Environmental Program Specialist Ed Snizek said Renovate had a "high degree" of success when used to treat milfoil in an 11-acre area of Lake Luzerne, although the plant hasn't been eliminated completely. He said a large die-off of non-native snails was observed two days after the chemical was applied, but there was no "conclusive" explanation for what happened. Snizek said a study has found this species of snail has a history of "synchronized die-off events" in Northeast lakes, and he noted that when Renovate was applied to Cazenovia Lake, near Syracuse, it had no impact on two native snail species.

APA board members raised no objections to the use of the herbicide in Loon Lake, although Commissioner Richard Booth referenced the Council's call for a public hearing during the discussion.

"I don't think we ought to do that now; I think this should go forward," he said. "But I do think the agency should seriously consider a formal hearing dealing with this issue generally. We've been doing this on a case-by-case basis. The Adirondacks is a special place, and we're going to get more of these applications in the future. We ought to look at this in a more detailed way than we have."

While the APA currently has no other pending applications for the use of Renovate, Loon Lake Park District Association President Edward Griesmer said after Thursday's meeting that groups like his are looking at every possible tool they can use to combat invasives.

"Lake associations are first responders in trying to deal with invasive species," he said. "We've got a war going on here. It's not a problem that's going away."